HR: 1340h
AN: AE23A-0903    [Abstracts]
TI: Production of Nitrogen Oxides by Laboratory Simulated Transient Luminous Events
AU: Peterson, H
EM: haroldp@dri.edu
AF: Desert Research Institute, Division of Atmospheric Sciences, 2215 Raggio Parkway, Reno, NV 89512, United States
AU: Bailey, M
EM: bailey@dri.edu
AF: Desert Research Institute, Division of Atmospheric Sciences, 2215 Raggio Parkway, Reno, NV 89512, United States
AU: Hallett, J
EM: hallett@dri.edu
AF: Desert Research Institute, Division of Atmospheric Sciences, 2215 Raggio Parkway, Reno, NV 89512, United States
AU: * Beasley, W
EM: whb@ou.edu
AF: University of Oklahoma, School of Meteorology, 120 David L Boren Blvd, Suite 5900, Norman, OK 73072-7307, United States
AB: Restoration of the polar stratospheric ozone layer has occurred at rates below those originally expected following reductions in chlorofluorocarbon (CFC) usage. Additional reactions affecting ozone depletion now must also be considered. This research examines nitrogen oxides (NOx) produced in the middle atmosphere by transient luminous events (TLEs), with NOx production in this layer contributing to the loss of stratospheric ozone. In particular, NOx produced by sprites in the mesosphere would be transported to the polar stratosphere via the global meridional circulation and downward diffusion. A pressure-controlled vacuum chamber was used to simulate middle atmosphere pressures, while a power supply and in-chamber electrodes were used to simulate TLEs in the pressure controlled environment. Chemiluminescence NOx analyzers were used to sample NOx produced by the chamber discharges- originally a Monitor Labs Model 8440E, later a Thermo Environment Model 42. Total NOx production for each discharge as well as NOx per ampere of current and NOx per Joule of discharge energy were plotted. Absolute NOx production was greatest for discharge environments with upper tropospheric pressures (100-380 torr), while NOx/J was greatest for discharge environments with stratospheric pressures (around 10 torr). The different production efficiencies in NOx/J as a function of pressure pointed to three different production regimes, each with its own reaction mechanisms: one for tropospheric pressures, one for stratospheric pressures, and one for upper stratospheric to mesospheric pressures (no greater than 1 torr).
DE: 0317 Chemical kinetic and photochemical properties
DE: 0320 Cloud physics and chemistry
DE: 0340 Middle atmosphere: composition and chemistry
DE: 3324 Lightning
SC: Atmospheric and Space Electricity [AE]
MN: 2007 Fall Meeting